In the production of corrugated boxes, the corrugated boards produced at a corrugated machine are converted to blanks of a desired shape then folded and glued to form boxes, in a corrugated finishing machine commonly know as a flexo folder gluer. The boxes exit from being folded and glued as a constant stream of boxes. The stream of boxes must be placed in stacks that are manageable for shipping. A counter ejector takes the stream of boxes from the flexo folder gluer and counts and stacks the boxes in to stacks of desired size.
In order to maximize production, the machine is not stopped or even slowed down to allow for separation of the boxes into stacks. Instead, a set of fingers is inserted into the flow of boxes to temporarily support the boxes entering the stacker and separate them from the underlying stack, while the underlying stack is moved. U.S. Pat. No. 3,892,168 discloses a counter ejector having a series of fingers for interrupting the flow of boxes and is incorporated by reference.
The number of boxes delivered in a selected interval is dependent on the size of the box and the complexity of the box, such as number of cut-outs and style of printing. These factors have a bearing on the speed of the machine. Therein because of differences in the production speed, the size of the boxes and in addition the size of the stack desired, the fingers are not consistently inserted at the same time from run to run. The timing for insertion of the fingers must be set properly to separate the stream into stacks. A machine operator may manually adjust the timing of the insertion of the fingers according to the speed the boxes are being produced, however the process of adjusting the timing is trial and error. If the fingers are inserted into the flow of boxes at the improper time, the fingers will not be inserted between boxes but rather hit a box therein causing the boxes to jam.
It is desired to automatically insert the fingers at the correct time to stop the flow of boxes without creating a jam to eliminate operator adjustment of the timing.